A term originating in military organization theory, but now used more commonly in business management, particularly human resource management, span of control describes the number of subordinates that report to each manager (or to each military officer).

In the hierarchical business organization of the past it was not uncommon to see average spans of 1 to 10 or even less. That is, one manager supervises ten employees on average. In the 1980s there was a flattening of organizational structures causing average spans to move closer to 1 to 100. This was made possible by the introduction of inexpensive information technology that replaced many middle managers (whose main task had been to collect information from operational managers, compile it, and present it to upper management). Computers also made feasible the task of managing larger groups.

The current shift to self-directed cross-functional teams and other forms of non-hierarchical structures, have made the concept of span of control less salient.

Theories about the optimum span of control go back to V.A. Graicunas. In 1933 he used assumptions about mental capacity and attention span to develop a set of practical heuristics. L.F. Urwick (1956) developed a theory based on geographical dispersion and the need for face-to-face meetings. In spite of numerous attempts since then, no convincing theories have been presented. This is because the optimum span of control depends on numerous variables including organizational structure, available technology, the functions being performed, and the competencies of the manager as well as staff.